docs: def expand_src_param(values, shp_params):
      """
      Expand hazardlib source attribute (defined through list of values)
      into dictionary of shapefile parameters.
      """
      if values is None:
          return dict([(key, None) for key, _ in shp_params])
      else:
          num_values = len(values)
          return dict(
              [(key, float(values[i]) if i < num_values else None)
                  for i, (key, _) in enumerate(shp_params)])